Heating and cooling system

ABSTRACT

An air-conditioning system for multiple zone building units, including heating and cooling, in which the delivery of a heated or chilled liquid heat exchange medium (water) to heat exchange units (fan coils) in each zone to be conditioned, is individually controlled by a thermostat in each such zone, and which includes a single pipe closed distribution system for each individually controlled zone for circulating the heated or chilled water, to each zone separately and alternatively and in opposite directions through its single pipe closed distribution system, a heater adapted to supply heated water to the closed distribution system of each individually controlled zone, a chiller adapted to supply chilled water to the closed distribution system of each individually controlled zone, and valve means in the closed distribution system in each zone for controlling the supply of heated water to the closed distribution system in each zone, and for returning it to the heater, and for controlling the supply of chilled water to the closed distribution system in each zone, and for retuning it to the chiller, the supply of such heated and chilled water to the closed distribution system in each zone being separately and alternatively controlled by the thermostat in each controlled zone.

United States Patent [72] Inventor James Patrick Donnelly PrimaryExaminer-Charles Sukalo 112 11auerh11lSt., North Reading, Mass. A r ey-Pr r & Meyer 01864 [21] App]. No. 822,601 22 Filed 4. 1 9 ABSTRACT: Anair-conditioning system for multiple zone 45 Patel-ed 1,120,197;building units, including heating and cooling, in which the delivery ofa heated or chilled liquid heat exchange medium (water) to heat exchangeunits (fan coils) in each zone to be conditioned, is individuallycontrolled by a thermostat in each such zone, and which includes asingle pipe closed distribution system for each individually controlledzone for circulating the heated or chilled water, to each zoneseparately and alter- [54] HEATING AND COOLING SYSTEM nativelyand inopposite directions through its single pipe 8 Claims, 10 Drawing Figs.closed distribution system, a heater adapted to supply heated water tothe closed distribution system of each individually U-S- controlled zonea chine adapted to supply water to 65/50 the closed distribution systemof each individually controlled 1 i 3/00 zone, and valve means in theclosed distribution system in of 50, each zone for controlling the upplyof heated water to the closed distribution system in each zone, and forreturning it to the heater, and for controlling the supply of chilledwater to [56] References CM the closed distribution system in each zone,and for retuning it UNITED STATES PATENTS to the chiller, the supply ofsuch heated and chilled water to 2,492,757 12/1949 Meek 165/22 theclosed distribution system in each zone being separately 3,109,48611/1963 Hansen 165/22 and alternatively controlled by the thermostat ineach con- 3,l27,929 4/1964 Ringquist 165/22 trolled zone.

L I T-l-I Q5 50 i P 45 D 0 50 1 -|s l 1 $5 FAN COIL I =jf FAN 3o L40 FANi COIL APT A l APT. A-i l v-l5 505i so-il 3o2- B 3:WAY c i 0 8 av PAssBY-PASS VALVE VALV vA Q j A i ae ies /58 .1458 24 I24 IQ/AIL "Eg 0 A T.i I I FROM APT. A-i TO APT. M I o A PT 2 i I FROM APT. 2 To APT. 22 T AP3 Fno 5gT 3 J 0M APT. 3 To APT. 3 '|22 'l To Ag 9 l l i Ay r. 9 IIFRQMAPTA lToAPr. i T 553} FFRQMPLQJ I new APT. 5 TO APT. 5 i 'rI'QAELQFFRQLPLU FROM APT. 6 To APT. 6 l-OT WtTEi 2o nor WATER CHILLED WA ER 1CHILLED WATE so RETURN MANIFOLD I RETURN MANIFOLD FEED MANIFOLD LJ FEEDMANIFOLD HOT WATER SOURCE CHILLED WATER SOURCE PATENTEUJULZOIHH3,593,780

SHEET 3 BF 5 JAMES P DONNELLY lnvenfor A Iomey PATENT-EB JIILmIIIII 3,593 7 8 O SHEET LI 0F 5 FIG 4 .l..d .V..4- ....m TO SINGLE PIPE l5 FROMTHRU PIPE l5 APT. A-I IN APT. A-I

RETURN TO HOT WATER HOT WATER FROM SOURCE SOURCE FROM TO PIPE I5 PIPE I5T IN APT. A-I APT. A-I

RETURN TO CHILLED WATER SOURCE CH ILLED WATER FROM SOURCE JAMES F?DONNELLY fnven/or A forneys PATENTEmuLzo m1 3 598. 78 O SHEET 5 OF 5JAMES P. DONNELLY By f 4/ may HEATING AND COOLING SYSTEM SUMMARY OF THEINVENTION Briefly, my inventioncomprises an air-conditioning system formultiple zone building units, including both heating and cooling, inwhich the heating and cooling medium is delivered to fan coils in eachcontrolled zone through a single pipe closed distribution system to eachcontrolled zone, flowing in said pipe in opposite directions, separatelyand alternatively as controlled by a thermostat in each controlled zone.A heater or boiler provides a supply of heated water, and a chilling orrefrigerating unit provides a supply of chilled water. The heated orchilled water is delivered alternatively to the single pipe closeddistribution system in each controlled zone, as controlled by thethermostat in each zone, through two specialized three-way valves ateach end of the single pipe closed distribution system. The heated wateris delivered to the single pipe closed distribution system in eachcontrolled zone through the first three-way valve, and is returned tothe heater through the second three-way valve. Conversely the chilledwater is delivered to the,same single pipe closed distribution system ofeach controlled zone in the opposite direction, entering through thesecondthree-way valve and returning to the chiller through the firstthree-way valve.

Another feature of my invention is a control panel for each zone to becontrolled, which includes a replaceable plug-in transformer, relay, anda replaceable power head for the three-way valves provided in each zone.

Objects and advantages of my air-condition system include:

I. reduced installation costs, amounting to savings in labor andmaterials of at least 30 percent;

2. savings from fewer holes cut in flooring, walls and timbers, whichare reduced 75 percent in size and number, because of running one pipeinstead of four, to each controlled zone;

3. savings in many smaller pipes, because smaller pipes can be used ineach controlled area;

4. efficiency of operation, because there is no mixing of the hot andchilled water, so that when a change is made from heated to chilledwater, for instance, the fans to the coils are not actuated until thechange over has been effected.

5. individual control foreach controlled area, with one area beingheated more than another, and while another is even being cooled, forinstance;

6. with my single pipe system, with a single thermostat controlling bothheating and cooling, it is impossible for the system to heat and coolthe same controlled area at the same time, as frequently occurs with asplit system, with resultant inefficiency and expense;

7. with my control panel having replaceable plug-in transformers andrelays, and a replaceable power head to actuate the three-way valve, mysystem can be maintained and operated at minimum expense by an unskilledcustodian, and does not require the services of a stationary engineer oran electrician;

8. my system further readily lends itself for total energy installationswhere total requirements of electricity, heating and cooling areprovided from one total energy source;

9. in short, my system provides individual control of heating andcooling for individual units as desired, as in the conventionalfour-pipe system, but at substantially less cost of installation andoperation, and with substantially greater efficiency and simplicity ofoperation with resultant lesser cost.

REFERENCE THE DRAWINGS FIG. I is a diagram of my heating and coolingsystem'for multiple zone building units;

FIG. 2 is a wiring diagram of the control panel;

FIG. 3 is a wiring diagram of the thermostatic control of the three-waybypass valves, as installed by the electrical contractor for themultiple zone building unit;

FIG. 4A is a vertical sectional view of one of my three-way bypassvalves;

FIG. 4B is a diagrammatic view of the operation of my three-way bypassvalves on the heated water side;

FIG. 4C is a diagrammatic view of the operation of my three-way bypassvalves on the chilled water side;

FIG. 5A is a vertical section of the Venturi fittings used in my heatingand cooling system operating to conduct the heated water;

FIG. 5B is a vertical section of the Venturi fittings used in my heatingand cooling. system operating to conduct the chilled water;

FIG. 6A is a vertical section of the check valve in open positron;

FIG. 6B is a vertical section of the check valve in closed position.

DETAILED DESCRIPTION My heating and cooling system is designed formultiple zone building units, which will include apartment houses,hotels, motels, such as cottage type hotel units, college dormitories,office buildings and in short any multiple units heated and cooled froma central plant, where it is desired to give an individual unit controlover its own heating and cooling requirements. Even if the heating andcooling system is not tailored to the whims of individual occupants ofunits, there are many situations as in large apartment houses, wheredifferent exposure to sun and wind conditions will require varyingtreatment of the heating and cooling provided for the different multipleunits. While I describe my system as a heating and cooling system, itseems that a more apt phase is air conditioning, which will beunderstood to include both heating and cooling.

As shown herein, particularlyin FIG. 1, one hot water feed line, ahotwater return line, a chilled water feed line and a chilled waterreturn line are shown leading to and from apartment No. 1. But, FIG. Iis a'diagram of my system adapted for heating and cooling sixapartments, Nos. 1 to 6 in an apartment house, and it will be understoodthat the feed return lines, the bypass valves and the like, as shown inFIG. I, will be duplicated for the apartments Nos. 2 to 6, and for asmany other controlled units or areas as there may be in the multiplezone building units.

FIG. I is a diagram showing the mechanism and operation of my heatingand cooling system. As shown in FIG. 1, 10 represents the hot watersource, which is a conventional type of heater or boiler, fired by gas,oil, or electricity, as desired. The heating medium is water preferably,although it can be other suitable liquid media. A pump 12 is installedin the common main line I4 leading to each controlled zone which leadsfrom the source 10 to the hot water feed manifold shown generally at 20.Pump I2 is continuously operating, its operating being maintained by anAquastat (not shown) located outdoors, set to cut off when the outdoorstemperature reaches 70". F. The hot water feed manifold 20' leads to thehot water feed line 15, and includes as parts a small portion of the hotwater feed line IS, a small portion of the chilled water return line(since the chilled water returns through the first threeway bypass valve30-1 to the chilled water source, (described below), a shutoff valve 24,a check valve 28, and the first three-way bypass valve 30-1, all mountedon the hot water feed line I5 leading to apartment No. A-l. It will beunderstood that each manifold 20 and its component parts for eachapartment are mounted in a convenient location, such as the basement orthe janitors office, or closet, and are outside of the apartment.Shutoff valve 24 is a manual shutoff valve, to be shut off when aparticular apartment is vacant, or otherwise is not air-conditioned. Thecheck valve 28, shown in FIGS. 6A and B and described in detail below,is provided as a safety valve to prevent any leakage or mixing of thehot and chilled water flowing through the first three-way bypass valve30-], and is unnecessary if valve 30-A in bypass valve 30 positivelyseats so as to prevent any mixing of the hot and chilled water in line115.

The three-way bypass valve 30 is a modified valve of novel constructionso far as I am aware, although three-way bypass valves as such as knownto be old. The three-way bypass valve is shown in FIG. 4A and itsoperation is shown in FIGS. 48 and 4C, and is described in detail below.The valves 30 (FIG. 4A) are Model No. 560 Taco bypass valves,manufactured by Taco, Inc. of Cranston, RI. It suffices for presentpurposes to state that the first valve 30 includes three ports, port Aat the bottom, through which the hot water enters, to exit through portB and thence passing in a clockwise direction through the feed line 15,which traverses the perimeter of apartment No. A-l, FIG. 1, the bordersof which are shown by the dashed line outlining it. In FIG. I, theapartment AI is shown as a fourroom apartment, containing kitchen,dining room, living room and bedroom, and for that reason a series offour heat exchange units 40 are shown arranged on the feed line 15traversing the apartment, each heating one room. But it is understoodthat more or less of the heat exchange units 40 can be used as needed.As shown the heat exchange units 40 are fan coils of standardconstruction, which include a coil (not shown) through which the heated(or chilled) water passes, and a motor-operated fan which blows ambientair across the coil, thus heating or (chilling) the air and the roomaccordingly. A pair of Venturi fittings or tees 50 is mounted on thefeed line 15, a pair for each fan coil unit 40, which fittings and theiroperation are shown in FIGS. 5A and 5B and are described in detailbelow. The use of these Venturi fittings is not essential to thesuccessful operation of my system of heating and cooling, but their useis desirable and preferable. However, the use of some restrictive means,such as a restricted or narrower pipe is desirable at each fan coil 40to maintain uniform heating and to prevent loss of heat at eachsuccessive fan coil. But such restrictive means requires such carefulengineering calculations and experimenting, that the use of the Venturifittings is much to be preferred.

As shown in FIG. 1, a pair of three-way bypass valves 30 are used foreach controlled area, here shown as apartment A-l, and the second valve30-2 mounted in the feed line 15 after the last fan coil unit 40. Theconstruction of valve 30-2 is identical with valve 30-1, except that itis turned around back to front, so that port B of valve 30-2 is now onthe right as viewed in FIG. I, and port C is on the left. But ports Band C are the same in each valve 30. Here the operation of valve 30- 2is such that the heated water return passes through valve 30- 2,entering at port B, and exiting through port C, into the return portion58 of feed line 15, here shown conventionally in dot-dash line, to passinto the hot water return manifold 60, and back to the hot water sourceI0, when it is reheated, and recirculated again.

The chilled water cycle is the exact reverse of the hot water cycle,with the chilled water passing in the opposite direction (i.e.counterclockwise FIG. I) through valve 30-2 the single pipe 15 and valve30-1 to return to the chilled water source 110. Chilled water source 110is a conventional refrigerating unit, including motor, compressor andcondenser or is of the absorption type (not shown). Each component partin the chilled water cycle is a duplicate of its counterpart used in theheated water cycle, and includes main line 1 I4, feed line I15, chilledwater feed manifold 120, which in turn includes the shutoff valve 124,the check valve I28, and the second threeway bypass valve 30-2. Here, asshown in FIG. I, the chilled water enters bypass valve 30-2 throughbottom port A, exits through port B, to pass in a counterclockwisedirection through the single feed line 15, fan coil units 40, and thenceon its return cycle through the first three-way bypass valve 30- 1,entering through port B, and exiting through port C, through the chilledwater return line 158 (not used by the hot water system) to return tothe chilled water return manifold 160, and thence back to the chilledwater source I10, to be chilled and recirculated again.

As an illustration, in operation, in my single pipe system, when heatingis desired the hot water is heated to approximately 200 F. in the hotwater source and is delivered by pump 12 to the feed line 15 ofapartment A-l to each fan coil unit 40 successively. The hot waterreturns to the hot water source 10 at about 180 F., a temperature dropof about 20, without loss of heating efficiency and is there reheatedagain to approximately 200 F. It will be understood that the temperaturecan be varied, as desired-less temperature being required in warmerclimates, and greater heat loss is thus permissible, with lesser heatingefficiency. Similarly the chilled water when cooling is called for, ispumped out by pump 112 at about 42 F. and in going through a single feedline 15 in the controlled area (apartment A-l) to each fan coil unit 40successively experiences a heat rise of about 10 to 52 F. and is thenreturned to the chilled water source 110, to be rechilled toapproximately 42 F. The chilled water range is necessarily morerestricted, to avoid freezing and ice formation.

In operation, also, it will be understood that the thermostat T inapartment A-l (FIG. 1) will be set to maintain a temperature in theapartment of 70 F., within a variation of 1% F. above or below 70 F. Iffor instance, the temperature in apartment A-I goes below 70 F. and thesituation calls for more heat, thermostat T closes a switch in thepowerhead 36 to actuate valve 30-2, opening valve D therein to allow thehot water in feed line IS to pass through valve 30-2 from port B to portC by closing off port A and thence return through feed line 15 to thehot water source 10. At the same time that valve D in valve 30-2 opens,port A, being on the same stem 32 with valve D closes. This prevents anymixing of the heated and chilled water. The hot water pump 12,constantly operating, maintains the hot water in line 15 under constantpressure. It is understood that a bypass relief around valve 30-2 whenit is closed to circulation of heated water may be provided, if desired.Valve D in three-way valve 30-2, under actuation from the thermostat Topens slowly, and the hot water begins to move through the feed line 15in apartment A-1, and after an interval or timelag of about seconds,switch 39 on thepowerhead 36 on three-way valve 30-2 closes to operatethe motors to the fans in each fan coil unit 40 in apartment A-l, whichare now being supplied with 200 F. hot water to bring the temperature inapartment A-l back to 70F.

When the temperature in apartment A-l reaches 70 F. (plus 195 F.tolerance or variation) thermostat T closes valve D in three-way valve30-2, so that hot water no longer flows through three-way valve 30-2,and after a short time interval, turns off the motors to the fans ineach fan coil unit 40. This condition remains until the temperature inapartment A-l again drops below 70 F. when the heating cycle isrepeated.

Normally, in a temperate climate during the winter season, only heatingwill be required in all units of the controlled area. The chilled watersource and pump 112 is thus maintained in an inoperative condition beingcontrolled by an outside thermostat or Aquastat (not shown), set tooperate at 70 F. outside temperature. This is optional equipment, and isnot necessary for operation of the system, as this can be done manually,if desired. Likewise, in the summer season normally only cooling will berequired in the units of the controlled area. Thus the hot water source110 and pump 112 can be maintained in an inoperative condition, beingcontrolled by an outside thermostat or Aquastat (not shown) set tooperate at 75 F. outside temperature. Thus by this means an occupant ofa controlled area cannot turn on either heating or cooling unlessoutside temperature conditionsjustify or require it.

FIG. 2 is a wiring diagram of the control panel, which is placed in aconvenient location for janitor service, and in a high-rise apartmentbuilding, one would preferably serve each floor. As shown in FIG. 2,panel is provided for increments of three apartments. The panel itselfis a NEMA (National Electrical Manufacturers Association) class I paneland box, and includes a circular molded plastic panel having 8 pmsockets for one transformer to be plugged into said sockets. Theseactive sockets are numbered 2, 3, 6 and 7, the others being holdingsockets. One transformer is provided for each of apartments orcontrolled area and below are arranged three additional similar panelsfor relays, one for each of three apartments, to be plugged insimilarly. Here the active sockets are 2 and 7, and 6 and 8, the othersbeing holding sockets. As

shown, alternating current is lead in at 110 v., is stepped down by thetransformer to 24 volts as delivered to the thermostat T and thence tothe three-way valves, as shown in FIG. 3, which shows the wiring diagramcontrol for the thermostats and valves.

In FIG. 3, the right-hand numbered column corresponds to the junctionpanel (right-hand column of FIG. 2) bearing numbers vertically downwardfrom 1 to 11. It will be understood that the control panel (FIG. 2) issupplied intact by the heating contractor and FIG. 3 is the wiringdiagram to be followed by the electrical contractor on the particularinstallation. Junction terminal 1A is terminal l-T on FIG. 3 leadingfrom the transformer. As shown in FIG. 3, the terminals in theright-hand column of FIG. 3 are the same numbered terminals as in FIG.2, to which the electrical contractor connects in the panel box. Asshown, the thermostat T in apartment A-ll leads alternately to the twothree-way bypass valves at I-V, to complete the circuit through 2-V and3-A to operate valve 30- 1 for cooling or valve 30-2 for heating, 3-V isthe auxiliary switch of valves 30-] and 30-2 which in turn throughjunction terminal 4A operates the relay, which actuates the motors tothe fan coils 40 in apartment A-l. In each apartment the upper series ofterminal l-V, 2-V and 3-V are to valve 30-] for cooling and the secondseries of terminals 1-V, 2-V and 3-V below are to valve 30-2 for heatingand are operated by the thermostatT in the same manner.

The wiring diagram in FIGS. 2 and 3 operates as follows:

each is a part of hot water feed manifold, and hot water return manifoldrespectively, as well as parts of the chilled water feed and returnmanifolds in my single pipe system. Each valve 30 operates so that theheated water and chilled water, pass separately and alternatively inopposite directions through the single pipe 15. As shown in FIG. 1, theheated water passes through single pipe in a clockwise direction, andthe chilled In FIG. 2 left-hand column terminals 1 and 2 provided I 10-volt AC alternating current to the transformer which is plugged into thetop panel 70. Terminals 2 and 3 of the top panel become the source ofcurrent for the 24-volt control circuit (FIG. 2, right-hand column).Terminal 2 of the 24-volt column leads to terminal 1A of FIG. 2, andthence to terminal l-T of FIG. 3. when heat is called for terminal I-Tconducts electric current through the thermostat T to terminal S-T, andthence to the control valve -2 of terminal IV. This completes a circuitto provide power to open the control valve 30-2. In FIG. 3 thethermostat T in apartment A-I thus described is set up for heating.Referring to FIG. 2, terminal 3 of panel 70 thus is the low side of the24-volt circuit. Terminal 3 of panel 70 of FIG. 2, and 3A of FIG. 3 isthe same terminal. 3A is between 2-T and 5-T of the thermostat circuitterminal. 3A of FIG. 3 is common to 2V of all bypass valves. So 1V and2V closes the circuit that operates the valve bypass 30-2. The powerhead of the bypass valve 30-2 of FIG. I now activates 3- V circuit ofFIG. 3, and 3-V completes the circuit back to 4A of FIG. 2. Terminal 4Athen completes a 24-volt circuit of the relay for apartment 1 therebyoperating terminalNo. 6 of the relay panel 75 which operates the motorsto the fan coils 40 in apartment No. 1 to deliver heat to the apartment.It will be understood that FIG. 2 can be put into a printed circuit.

It is understood that the cooling is the exact reverse. The onlydifference when the thermostat T calls for cooling is that 5T becomesinactive, and, 2T becomes active which operates valve 30-1 of FIG. l toallow chilled water to circulate through feed line 15. Then terminals 2Vand 3-V become common to all valves 30-1 and 30-2 so that the rest ofthe circuit becomes the same. Only the valves 30-1, and 30-2 areenergized when it is hot or cold.

The three-way bypass valves 30-1 and 30-2, FIGS. 1, 4A, 4B and 4C, willnow be described in more detail. As stated above, valves 30-1, and 30-2are identical valves, except that they are turned around front to rear.Thus in FIG. 1, valve 30-1 shows port B on the left side of the valve,and in valve 3-2, it appears on the right side. Forts B and C in bothvalves 30-1 and 30-2 are thus the same in each valve, although appearingon opposite sides to each other; So far as I am aware, valves 30-1 and30-2 are of novel and unique construction. As best shown in FIG. 4A,which shows valve 30-2 arranged as it appeared in FIG. ll mounted onfeed line IS, the valves 30 include an entering port A at the bottom, aside port B, and a side port C. A pair of valves 30 are mounted on eachend of the feed line 15 leading to each controlledarea, such asapartment A-1, and

water in a counterclockwise direction, but it will be understood thatthese directions of flow can be reverse.

As shown in FIG. 4A bypass valve .30 shows generally a hollowcylindrical body 31, having arranged therein a central verticallymovable stem 32, tensioned by coil spring 33, and carrying on its lowerend valve A-l, which seats against valve seat A-2 to close off entryport A, when stem 32 is moved downwardly by the power head, showngenerally at 36. At its midsection, stem 32 carries valve D, which seatsagainst valve seat D-l. It will be understood that ports 8 and C areclosed off from each other, except when valve D is open, and when valveD is "open port A is automatically closed, so that no water can enter orexit through port A. But when valve D is open water can pass from port Bto port C (or vice versa) through orifices 34 in side walls D-1 alsoforming part of port C. A metal bellows 35 encloses the upper part ofstem 32 to prevent leakage of water around the upper part of stem 32.

The power head 36 is of conventional construction, and hence is notshown in detail. Such power heads are manufactured and sold by Taco Inc.of Cranston, RI. It suffices to say that the power head includes avertically movable stern (not shown) actuated by a heat motor, operatedfrom the thermostat T in apartment A-l. It will be understood that theheat motor is a hollow flexible metal or electrical bellows containing agas which expands when heated electrically, and as it elongates, pushesdown stem 32 of valve 30-2, opening valve D and closing port A, andallowing water to pass from port B to port C, for instance, and allowingthe heated water to return to the hot water return manifold 60. Threeelectric terminals are provided on the side of power head 36 (FIG. 4A),which include terminal 37, which supplies power from the transformer at24-volts to operate the heat motor, terminal 38 operated from thethermostat T, which closes the circuit to operate the heat motor to pushstem 32 downwardly, and terminal 39. Terminal 39, as the heat motorelongates downwardly closes the circuit through an auxiliary switch tothe relay, which in turn closes the circuit to operate the fan motors inthe fan coils 40. It will be understood that the heat motor heats upslowly, and that there is an internal or timelag of about seconds beforethe heat motor closes the circuit to the fan motors after the valve Dhas opened to pass the heated water through valve 30-2 from port B toport C into the return feed line 15 to the return manifold 60. Thistimelag thus insures the circulation of hot water in the feed line 15 inthe desired range of 200 F., before the fan motors are turned on. Ahandle 36a, is further provided for manual operation of the valves 30-1and 30-2, in case power head 36 fails to operate for any reason.

FIGS. 48 and C show the operation of the three-way bypass valves 30-1and 30-2 on the heated water cycle, and on the chilled water cycle,respectively, as heretofore described.

FIG. 5A shows the construction and operation of the Venturi fittings onthe heated water side, and FIG. 5B shows the same on the chilled water.These are mounted on the feed line 15, to conduct heated water throughthe fan coil units 40 in the same direction as it flows through the feedline 1 5i.e. in a clockwise direction, as in FIG. 1with the chilledwater flowing in the opposite direction-i.e. counterclockwise, as inFIG. 5B. The Venturi fittings or tees 50 are of standard constructionand a pair of them are mounted on the feed line 15 in a reversedarrangement, preferably on 18-inch centers, on the entrance and exitside to a fan coil unit 40. As is well known Venturi fittings such as 50A and B include an inlet side 51, an outlet side 52, a slightlyrestricted orifice 53, a narrower or more restricted orifice 54, with abypass outlet 50A between the two orifices 43 and 44. As shown in FIG.5A the Venturi fitting 50 on the left 50A has the more restrictedorifice 54 on thedown stream side of the direction of flow of the heatedwater, which is shown to be in a clockwise direction; while the Venturifitting 508 on the right is reversed to 50A, with its narrower orifice55 on the upstream side of the direction of flow of the heated water.The result of this arrangement is that in operation Venturi fitting 50Aby a suction action pulls or bypasses a constant percentage(approximately 30 percent) of the heated water through the fan coil unit40 from the feed line 15, in the same direction of flow and returns itto the feed line through the second Venturi fitting on the right, as inFIG. A. The purpose, of course, is to provide heated water to allsuccessive fan coil units 40 in a controlled area, as apartment A-l, atas near a constant temperature as possible, so that the heating providedsuccessive fan coil units will be substantially uniform throughout acontrolled area.

FIG. 5B shows the construction and operation of the Venturi fittings, onthe chilled water side. Here, of course the construction is the same,but the operation is in reverse, with the direction of flow of thechilled water being reversed-in a counterclockwise direction. Thisarrangement of the Venturi fittings 50A and B make it possible tocirculate the heated and chilled water in opposite directions through asingle pipe heating and cooling system. As explained above, the use ofthe Venturi fittings as described, is highly desirable, if uniformheating conditions are desired to be maintained between success ive fancoil units in a controlled area. Other restrictive means are possible,but would normally require such careful engineering calculations tomaintain uniform heating conditions between successive fan coil units asto make their use impractical.

FIG. 6A and B shows the check valve 28 in open position, and closedposition respectively. Check valve 28 is of standard construction and inoperation permits the flow of liquid through it in one direction (FIG.6A) but prevents its flow through it in the opposite direction (FIG.68). For this purpose a hinged flap valve 29 is provided which openswith the flow of liquid through it from right to left in FIG. 6A, butcloses against seat 29a to prevent the flow of liquid through it in theopposite direction (FIG. 6B). A check valve 28 is mounted on the feedlines and 115 as shown in FIG. I, as a precaution to permit the flow ofheated water through port A in three-way valve 30-1, and chilled waterthrough port A in three-way valve 30-2, but not in the oppositedirection. This prevents the possible mixing of the heated and chilledwater, with consequent losses of heating efiiciency in-my single pipesystem.

It will be understood that variations and modifications may be made inmy single pipe heating and cooling system without departing from myinvention, as described in the appended claims.

I claim:

1. In an air-conditioning system for heating and cooling multiple zonebuilding units, which includes a source of supply of heated water,

a source of supply of chilled water,

a single pipe closed distribution system in each individual controlledarea connecting said sources of supply for conducting heated and chilledwater through each said closed distribution system,

heat exchange means in each said closed distribution system for eachindividual controlled area;

a single thermostat in each controlled area and means automaticallycontrolled by the thermostat in each individual controlled area forconducting heated or chilled water through the single pipe closeddistribution system in its area;

and means for returning said heated and chilled water each to itsrespective source;

said means controlled by said thermostat including a pair of three-waybypass valves each said bypass valve arranged at opposite ends of eachsaid single pipe closed distribution system, the first said bypass valveadjacent said source of supply of heated water, the second said bypassvalve adjacent the source of supply of chilled water each said bypassvalve in normal nonactuated position connecting said single pipe closeddistribution system to the respective said source of supply and inactuated position the first said bypass valve connecting said singlepipe closed distribution system with said means for returning chilledwater to its source and the second said bypass valve connecting saidsingle pipe closed distribution system with said means for returningheated water to its source;

a pair of check valves, the first said check valve arranged between thefirst said bypass valve and the said source of supply of heated water,the second said check valve arranged between the second said bypassvalve and the said source of supply of cooled water, both said checkvalves arranged to permit flow of water from the respective said sourceof supply to the respective said bypass valve but not in the oppositedirection;

said thermostat separately and individually actuating one said bypassvalve or the other, the first said bypass valve being actuated whenpassage of chilled water through said single pipe closed distributionsystem is called for and the second said bypass valve being actuatedwhen passage of heated water through said single pipe closeddistribution system is called for;

whereby heated or chilled water is conducted through said single pipeclosed distribution system in opposite directions as called for by saidthermostat.

2. An air-conditioning system as claimed in claim 1, in which said heatexchange means includes a fan and coil unit, in which a motor operatedfan forces air across the coil.

3. An air-conditioning system as claimed in claim 1, in which said heatexchange means includes a restrictive means for maintaining flow ofheated or chilled water at uniform temperatures to successive heatexchange means.

4. An ainconditioning system as claimed in claim 3, in which saidrestrictive means includes Venturi fittings leading to and from saidsuccessive heat exchange means in each controlled area.

5. An air-conditioning system as claimed in claim 1 in which the meansautomatically controlled by the thermostat in each controlled area alsoincludes power means for actuating the respective said three-way bypassvalve responsive to temperature conditions in each controlled area.

6. An air-conditioning system as claimed in claim 5, in which said powermeans for actuating said three-way bypass valves includes a controlpanel having a replaceable plug-in electrical transformer, a relay and apower head.

7. An air-conditioning system as claimed in claim 2 wherein each saidbypass valve includes means for actuating the fan in each said heatexchange means upon being actuated by said thermostat.

8. An air conditioning system as claimed in claim 7 wherein there is atimelag between when the bypass valve is actuated and when the valve inturn actuates the fan in each said heat exchange means.

1. In an air-conditioning system for heating and cooling multiple zonebuilding units, which includes a source of supply of heated water, asource of supply of chilled water, a single pipe closed distributionsystem in each individual controlled area connecting said sources ofsupply for conducting heated and chilled water through each said closeddistribution system, heat exchange means in each said closeddistribution system for each individual controlled area; a singlethermostat in each controlled area and means automatically controlled bythe thermostat in each individual controlled area for conducting heatedor chilled water through the single pipe closed distribution system inits area; and means for returning said heated and chilled water each toits respective source; said means controlled by said thermostatincluding a pair of three-way bypass valves each said bypass valvearranged at oppoSite ends of each said single pipe closed distributionsystem, the first said bypass valve adjacent said source of supply ofheated water, the second said bypass valve adjacent the source of supplyof chilled water each said bypass valve in normal nonactuated positionconnecting said single pipe closed distribution system to the respectivesaid source of supply and in actuated position the first said bypassvalve connecting said single pipe closed distribution system with saidmeans for returning chilled water to its source and the second saidbypass valve connecting said single pipe closed distribution system withsaid means for returning heated water to its source; a pair of checkvalves, the first said check valve arranged between the first saidbypass valve and the said source of supply of heated water, the secondsaid check valve arranged between the second said bypass valve and thesaid source of supply of cooled water, both said check valves arrangedto permit flow of water from the respective said source of supply to therespective said bypass valve but not in the opposite direction; saidthermostat separately and individually actuating one said bypass valveor the other, the first said bypass valve being actuated when passage ofchilled water through said single pipe closed distribution system iscalled for and the second said bypass valve being actuated when passageof heated water through said single pipe closed distribution system iscalled for; whereby heated or chilled water is conducted through saidsingle pipe closed distribution system in opposite directions as calledfor by said thermostat.
 2. An air-conditioning system as claimed inclaim 1, in which said heat exchange means includes a fan and coil unit,in which a motor operated fan forces air across the coil.
 3. Anair-conditioning system as claimed in claim 1, in which said heatexchange means includes a restrictive means for maintaining flow ofheated or chilled water at uniform temperatures to successive heatexchange means.
 4. An air-conditioning system as claimed in claim 3, inwhich said restrictive means includes Venturi fittings leading to andfrom said successive heat exchange means in each controlled area.
 5. Anair-conditioning system as claimed in claim 1 in which the meansautomatically controlled by the thermostat in each controlled area alsoincludes power means for actuating the respective said three-way bypassvalve responsive to temperature conditions in each controlled area. 6.An air-conditioning system as claimed in claim 5, in which said powermeans for actuating said three-way bypass valves includes a controlpanel having a replaceable plug-in electrical transformer, a relay and apower head.
 7. An air-conditioning system as claimed in claim 2 whereineach said bypass valve includes means for actuating the fan in each saidheat exchange means upon being actuated by said thermostat.
 8. An airconditioning system as claimed in claim 7 wherein there is a timelagbetween when the bypass valve is actuated and when the valve in turnactuates the fan in each said heat exchange means.